Preheat oven to 350 degrees. Trim the ends of each rhubarb pieces in case they are hard or damaged. Cut the rhubarb into 1/4 inch, long slices and dice into small pieces. Dice the strawberries and add those to the rhubarb as well. If you are using freeze dried strawberries, just put them straight into the rhubarb and mix. Rinse the peaches, cut in half, remove the pit and dice the fruit into small pieces. Toss the fruit in the coconut sugar, add the salt, lemon juice and cornstarch and toss until coated.
Pour the fruit mixture into 4 ramekin dishes about 6 inches long and 3 inches wide. Or, pour into a 9x13 pan while you make the crumble.
For the crumble, place the butter in a bowl and soften for 20-30 seconds. Add the coconut sugar, salt, cinnamon, oats and cornstarch. Toss until combined. Sprinkle the crumble mixture over the fruit mixture until covered. Bake at 350 for 15-20 degrees, or until the top is golden and the rhubarb is soft. Serve warm with vanilla ice cream.